Why is Alaska checking boats for tiny mussels? Scientists fear one hitchhiker could change its waters

Alaska is taking proactive steps to prevent the introduction of zebra and quagga mussels, two invasive freshwater species not currently established in the state. Officials are training specialists and inspecting watercraft to detect these harmful organisms as they continue to spread across the American West.

The urgency stems from recent discoveries, including the detection of zebra mussel environmental DNA in Utah’s Colorado River in September 2026. While this does not confirm an established population, it served as an early warning, prompting further sampling. The DNA was found near the Potash boat ramp, downstream from Moab and upstream of Canyonlands National Park.

What are Zebra mussels?

Zebra mussels, native to Eastern Europe and Russia, were first found in the United States in the late 1980s. They attach to hard surfaces, forming dense colonies that can clog water intake pipes, damage infrastructure, and outcompete native aquatic species. By filtering large amounts of plankton, they disrupt food webs and reduce food availability for native species, according to the U.S. Fish and Wildlife Service.

A tiny invader, a big warning

In May 2026, over 35 invasive species professionals participated in training at Alaska’s Kenai National Wildlife Refuge. Their training focused on detection methods such as sediment sampling, plankton nets, shoreline inspections, and environmental DNA testing.

The concern over these small creatures is significant because they can easily attach to boat hulls, propellers, rudders, and floats. Water trapped in bilges, ballast tanks, motors, and live wells can transport microscopic life stages to new water bodies. Alaska officials also caution that floatplanes can spread aquatic invaders between lakes.

How can a mussel hitch a ride?

These mussels have already demonstrated their ability to travel in unconventional ways. In August 2024, zebra mussels were found in Alaska hitchhiking on marimo moss balls, which are aquarium plants sold for home use.

Once established, the impact of these mussels can be substantial. They filter large quantities of food from the water, disrupt aquatic food webs, compete with native mussels, and can clog water infrastructure like pipes and canals.

Alaska's 24-foot close call

Alaska experienced a close call in 2025 when inspectors intercepted a 24-foot boat traveling from New York toward Alaska that was covered in suspected invasive mussels. The vessel was decontaminated and cleared before it could be launched in Alaska.

This incident highlights the primary challenge: the mussels do not need to swim into Alaska; they only need a ride. Alaska is actively searching for them before they can become established.